Stock feeding collet



Jai.. 2, 1934. M. H, REDMER 1,941,999

STOCK FEEDING COLLET Filed July 7. 1932 Patented Jan. 2, 1934 UNITED STATES PATENT GFFECE STOCK FEEDING COLLET Martin H. Redmer, Chicago, Ill.

Application July 7, 1932. Serial No. 621,147

5 Claims. (Cl. 29-62) This invention relates to new and useful improvements in stock feeding lcollets adapted for use particularly in feeding stock to screw machines. Y k f An object of the invention is to provide, broadly, a collet of greater gripping surface, with a uniform longitudinal pressure, to minimize wear and assure a positive feed of the stock for longer periods at high and low speeds.

Any slippage and failure of the collet accurately to feed the stock is costly and delays production..

It is essential in the operation of high speed machines to advance the stock a given distance upon thel forward Stroke. If the gripping members fail to hold the stock and allow the stock to slip upon each forward stroke, considerable material may be wasted before the operator can stop the machine and make the proper adjustment. On the other hand, a slight variance may not be noticeable until too late, thereby causing not only a waste of material but a loss of time in separating the defective pieces from the remaining stock.

This invention provides means for applying` equal pressure from end to end along the segmental gripping members, which means, when properly assembled, will prevent slippage between the gripping members and the stock, and effect a constant xed feed for considerably long periods without requiring attention.

A further object of the invention is to provide a stock feeding collet having a minimum number of parts and one which is easily and quickly assembled. To this end and for the purpose of applying uniform pressure upon the stock gripping members, a plurality of spring members, preierably bowed and of the leaf type, are provided to engage the gripping members and create the desired gripping tension for the quality or delicate finish of the stock. These leaf springs may be nested in grooved surfaces of the gripping members, and, due to being flat and square, if so desired, they may act as keys to prevent the gripping members from slipping.

Other objects and advantages of my invention will be apparent from the following detailed description taken in connection with the accompanying drawing-which forms a part hereof.

In the drawing,

Figure 1 is a side elevational view of the stock feeding collet embodying the invention;

Fig. 2 is a longitudinal sectional view of the device; and

Fig. 3 is a view showing the various parts in disassembled relation.

The invention embodied in the device illustra'ted in the drawing comprises essentially a plurality of stock gripping members 1 and 2 of segmental forrn, if so desired, although it is understood that they, may be of any form, and a corresponding number of bowed leaf springs .3 and 4 adapted to have their ends rest in grooves 5 and 6 formed, in the periphery of the gripping members.

It will be noted that spring members 3 and 4 are preferably of the leaf'type, although this is not essential, and are flat so that their, ends will rest against the walls of grooves 5 and 6, whereby to prevent stock gripping members 1 and 2 from slipping. These spring members Y3 and 4 act, accordingly, as keys due to their pressure against the inner wall of the body portion of the collet into which these parts are inserted.

This body portion may be in the form of a sleeve 7 having a shoulder 8 therein against which stock gripping members 5 and 6 abut. Sleeve 'l may be furnished with a threaded stud 9 for attaching the coliet to its support on the machine in any well known way. Stud 9 is cored, as indicated at l0, in the usual Way to allow the stock to pass through the collet, as shown in Fig. 1. A screw cap 11 is provided at the opposite end of sleeve 7. Cap 11 may thread into the end of sleeve 7, as shown in Fig. 2, which will hold stock gripping members 5 and 6 in position. Cap 11 is provided with a bore 12 of the size of the stock to be fed. When the stock enters the collet, gripping members 5 and 6 are spread against the tension of bowed leaf springs 3 and 4, whereby the desired tension is applied upon these gripping members to grip the stock and move it forwardly upon the feeding stroke oi the collet.

The gripping members 5 and 6 normally have an internal diameter less than the diameter of the stock. Insertion of the stock spreads these gripping members to provide a space 13 therebetween along their edges so that as the surfaces of the gripping members wear, spaces 13 will be diminished until the side faces of the gripping members engage. By removing cap 11, gripping members 5 and 6 may be removed, and the side faces of the gripping members ground whereby again to obtain the same effective internal diameter for the gripping members. This is an easy form of adjustment in the case of wear and assures that the operator may keep the gripping members in a condition positively gripping the stock and providing maximum gripping surface.

It will be noted that gripping members 5 and 6 may be made of different material such as metal,

loo

libre, rubber, bakelite, bronze, hardwood, or any other material that can be adapted for all classes of work. If these gripping members are made of tool steel, they may be heat treated to a glass hard temper. o

It will be also noted that leaf springs 3 and 4 act perpendicularly to the line of movement of the stock so as to apply a relatively uniformly distributed pressure longitudinally `along Astock gripping members 5 and 6. Consequently, itis im'- possible for stock gripping members 5 and 6 to more effectively grip the stock at any one point. The inner surfaces of both stock gripping members 5 and 6 are caused, in their entirety, to uniformly engage the stock, thereby assuring movement of the stock without slippage and eliminating possibility of scratches or marring of the finish of the stock. The tension of the springs may be readily varied, as may be desirable where the stock may require a different gripping pressure du'e to the character thereof, by varying the curvature of the bow formation.

Without further elaboration, the foregoing. will so fully explain the gist of my invention that others may, by applying current knowledge, readily adapt the same for use under varying conditions of service, without eliminating certain features, which may properly be said. to constitute the essential items of novelty involved, which items are intended to be defined and secured to me by the following claims.

I claim:

1. A feed collet comprising abody portion in y the formof a sleeve having a shoulder therein said shoulder, resilient means acting perpendicularly to the line of movement of the stock to apply a relatively uniformly distributed pressure longitudinally along said stock gripping members, and a cap for said sleeve at the end opposite to said shoulder.

2. A feed collet comprising a body portion in the form of a sleeve, stock gripping members having a bore therein, and longitudinally arranged leaf springs for urging said stock gripping members into stock gripping relation.

3. A feed collet comprising a body portion in the form of a sleeve, stock gripping members disposed witliin said sleeve and having opposed grooves in the periphery thereof, and bowed leaf springs in said grooves to urge said stock gripping members into stock gripping relation.

4. A feed collet comprising a body portion llaving a split sleeve inserted therein, and diametrically opposed resilient members acting longitudinally from end to end to apply uniform pressure to said split sleeve, said split sleeve having means to receive the engaging portions of said resilient members to prevent said split sleeve from slipping upon stock fe'd thereby.

5. A feed 'Collet comprising'- a hollow body portion,- a plurality of segmental stock engaging members, each having a longitudinal groove therein, a bowed leaf spring for eaeh segment, and means for retaining said segmentsi'n said body portion and said springs insaid grooves t'o prevent slipping o'f said segments with respect to the stock fed thereby. o

MARTIN H. REDMER.- 

